Save Rooms, or Save Points, are safe and holy areas within Dracula's Castle (or other locations) where a weary traveler can rest and restore their health. These rooms became a staple within the Castlevania series once the Metroid theme-styled game Castlevania: Symphony of the Night was released in 1997, and were implemented due to newer gaming systems no longer needing a password feature.
A save room usually features the statue of a goddess or an angel who heals the player. Enemies cannot appear inside a save room.
In Castlevania: Symphony of the Night, a polyhedron can be found spinning in midair instead; this transforms into a golden coffin, wrapping around Alucard for him to sleep inside. In that same game, Alucard manages to find a fake, purple-colored save room where he is attacked in his dreams by a Succubus.
In Castlevania: Harmony of Dissonance, Juste also finds floating polyhedrons inside of Save Rooms like those in Symphony of the Night. However, once activated, they will disappear in a flash of light and won't transform into a coffin.